Hello everyone. I'm new here and have been studying the forum and oven plans for a few weeks now. I'm about to start building my oven stand on an existing slab in my backyard and so I have a few questions about the curing of the cement and mortar:

1) I live in Houston and its July with August approaching. The days are usually in the high 80's in overcast and mid to high ninety's when its sunny. Humidity ranges from the high 60's to high ninety's this time of year. Nights are anywhere in the 70's. Are these particularly poor conditions for curing cement and mortar?

2) Do the conditions for curing cement differ from that of mortar?

3) I know that the curing of the dome is of particular importance b/c of the temperatures it sees, and basically its the main part that this is all about. So, are optimum conditions needed for the curing of the mortar in the cement stand? What about the hearth?

Mortar and concrete offer you contradictory conditions, but there is no significant difference twixt the two. When first poured or laid, both concrete and mortar should be kept wet, usually covered with wet sheeting or burlap, for several days. This allows the materials to set well without shrinking too much. They should be kept out of direct sunlight, covered with a tarp. After, say, three to four days, the sheeting should be left off and the mortar allowed to cure in a dry state out of direct sunlight. The curing, different from setting, of mortar or concrete is an exothermic process. It take 28 days for a full cure, but that does not mean you can't build on a slab, for example, before then.

Your weather conditions will greatly affect the first of these stages, but not so much the second. Members here who build in high heat areas will be better guides than I am, but these are the basic guidelines.

Ron
I'm impressed, we have in Texas since 1986 and there is no way I'm starting this time of year. the heat and humidity are a KILLER. I'm spending the next two months studying up and will then start in Sept. There is some great information in this forum and that in itself will take some time to research.
Dwight

They don't stop pouring slabs anytime of the year around here and imagine it is the same in Houston. I poured my base slab in July last year. Rented a dump trailer of pre-mixed cement and it took all of 20 minutes, highly recommended. previous advice is good, just keep it covered and damp for a couple of days. I also layed plastic in the bottom of the form to prevent wicking moisture out of the wet concrete and into the slab once it is dry, just like they did to my house slab.

I poured the hearth is Aug/Sept can't remember exactly and that was fun, NOT. It took 22 bags of the crack resistant concrete and I rented a two bag mixer.Then mixing the Vermiculite concrete and pouring on top the same day. Long day. Again keep covered and remember the insul concrete takes 5-7 days to cure to firm.

I highly recommend doing away with the insulating concrete layer and going with insulation board instead. Better insulator and alot less hassel. I also went ahead and used Durock for the hearth bottom form and then left it there. Worked out great not having to spend time cutting to fit and then trying to get out.

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